Marking charts....
Buy the cd, print out your route after you have drawn it on the computer. I use mileages rather than times for my check marks but to each their own. You have one A4 sheet at a time as you fly, with the laminated chart as well if you like in case you get a real mega diversion. Scribble away, then throw the used A4 sheets in the bin after landing. This way you can write in your positions during flight with a big x on the map with a time every time you get a positive fix. I used to use photocopies until the digital map arrived.....
Oh, and forget fancy kneeboards. A real ripoff. just buy a plain clipboard with a pen holder. Laminate anything you want to remember and glue it to the clipboard.
You don't need a DI for VFR. Fly from distant landmark (water tower, funny colour field, whatever) to distant landmark. For turns either time them or estimate a new reference before you start, then check the compass when stable wings level.
Use a 500 000 or 250 000 depending on your cruising speed.
......instructors like pulling the power when things are running smoothly
That is because the engine may do the job for them, so they like to know you might actually be able to park your a/c safely when you are on your own. You could even consider choosing a route that gives you an out in the event of silence up front, and allow this consideration to influence your choice of cruising altitude
Luddite.......I know, but it works.